Apparatus for cleaning gases



Dec. 24, 1940. R R, HARJMQN 2,226,127

APPARATUS FOR CLEANING GASES I Filed May 12, 1959 2 Sheets-Sheet l INVENTOR Zoga Z [Jar/@112.

ORNEY R. R. HARMON FOR CLEANING GASES APPARATUJ Filed M 12, 1939 2 Sheets-Sheet 2 INVENTOF Fofier/ Z iarmolz ORNEY rllllflfWlI/III/llllllll Patented D..." 24, 1940 PATENT OFFICE APPARATUS FOR CLEANING GASES Robert, R. Harmon,

Charlottesville, Va., assignor to Peabody Engineering Corporation, New York, N. Y., a corporation of New York Application May 12, 1939, Serial No. 273,230

6 Claims.

This invention relates to an improved and simplified apparatus for cleaning or purifying industrial gases or air and more particularly to a novel and improved apparatus of the general type which first removes the bulk of the coarse particles, then the fine particles of dust, fume or the like, and finally the tiny droplets of liquid which may be entrained by the gases.

In many gas cleaning operations it is desirable to use a minimum quantity of scrubbing liquid so as to reduce, as far as possible, the cooling effect of the scrubbing liquid on the gases, or to reduce the heat required for raising the scrubbing liquid to the temperature of the gases. Furthermore, in the treatment of certain gases containing corrosive substances; such as sulphur oxides along with large quantities of dust, for example gases encountered in pulverized coal-fired furnaces, scrubbing with water tends to saturate the gases with water vapor, with aconsequent lowering of the gas temperature. These two factors permit the corrosive character of the sulphur compounds to become active and to attack more readily the materials of construction, It is desirable, therefore, to reduce the quantity of scrubbing water to a point such that thetemperature of the gases is not lowered to a value where subsequent corrosive action occurs.

Another important advantage in reducing the quantity of scrubbing liquid is to simplify the problem of disposal of the liquid and of the removed solids. It has, however, heretofore been dimcult to secure a great intimacy of contact between gas and liquid without circulating large quantities of liquid through the gases, or employing complicated or expensiveequipment. It I is accordingly an object of the present invention to provide novel and improved means for ob-v taining the desired cleaning action with a minimum amount of scrubbing liquid.

Another object is to provide a simple, dependable and eflicient apparatus of the type above indicated. 7

Another object is to provide such an apparatus which is capable of producing an intimate contact between the gas and liquid with the use of a minimum amount of liquid.

Another object is to provide an apparatus of the above type which is substantially self cleaning.

Another object is to provide an apparatus of the above typewhich is constructed and arranged so as to remove efficiently any droplets of scrubbing liquid which may be entrained in the gases during the scrubbing operation.

Another object is tojprovide an apparatus of the above type which'is cheap and simple to construct and dependable and efficient in operation.

Various other objects and advantages will be appar'ent as the nature of the invention is more 5 fully disclosed.

Although the novel features which are believed to be characteristicof this invention are particularly pointed out in the claims'appended hereto, the invention itself will be better understood by 10 referring to the following description, taken in connection with the accompanying drawings, in which a specific embodiment thereof has been set forth for purposes of illustration.

- In the drawings:

Fig. 1 is a side elevation, partly in section, of a gas scrubbing apparatus embodying the present invention; I

Fig. 2 is a horizontal section taken on the line 22 of Fig. 1 with parts broken away; I A 0 Fig. 3 is a vertical section taken on line 3-3 ofFigJL Fig. 4 is an enlarged, section taken on the line 4-4 of Fig. 2, showing the construction of thebaflle plates; I v

Fig. 5 is a section taken along the line 5-5 of Fig. 1, showing the arrangement of vanes; and

Fig. 6 is a perspective view of one of the vanes.

Referring tothe drawings more in detail, the invention is shown as applied to an apparatus of ,30 the tower type comprising a vertical cylindrical shell or casing ll] having a conical bottom I l terminating in a central drain l2 through which the waste liquid and the entrained solid parti-: cles are withdrawn, and a conical top H termi- 35 nating in a discharge opening i5 for they scrubbed gases. A tangential gas inletopening I6 is located in the bottom portionv of the casing ID in a position to cause the gases to whirl or rotate within said casing as they progress spirally upward toward the discharge opening l5. This lower portion of the casing l0, containing the rotating gases above mentioned, my be considered to constitute a primary cleaning zone 20 in which the bulk of the larger particles are thrown 45 out of the gas centrifugally against the side walls of the casing. III and fall to the bottom H, from which they are removed through the drain l2.

The gases from the primary cleaning zone 20 50 then pass upwardly through a secondary cleaning zone 2| which comprises a circular plate 22, openings or orifices 23 therein, each of which is of a generalventuri shape, so as to impart a high velocity to the 55- for example 7 cover 42,

58 of course,

gases passing therethrough. A bathe-grid 24, comprising a plurality of strips 25 having outwardly extending baiiies 26 formed thereon and supported by transverse rods 21 secured to the plate 22 by convenient means, not shown, is disposed above the plate 22 in a position such that one of the baflles 26 is located in alignment with each of the orifices 23. As shown more clearly in Fig. 4, the gases passing through the orifices 23 impinge upon the surfaces of baifles 26 by which the fine dust or fume particles are caused to be entrapped in the liquid and removed therewith. T'he construction of this plate 22 and battle-grid 24 is more fully disclosed in my Patent 2,007,759 and only so herein as is necessary to an understanding of the present invention.

In order to obtain the proper cleaning action this construction of plate and baiiie-grid, as

in set forth in the above mentioned patent, it is necessary to maintain the under surface of the bailles 26 wet by means of a blanket of water disposed on the plate 22. It has been found, however, that when operating in this manner, the orifices 23 tend to clog, due to the deposition of particles removed from the gas.

In accordance with the present invention, a single means is provided for maintaining this blanket of water upon the plate 22 and for con tinuously cleaning the under surface thereof. In the embodiment shown, this means comprises a spray manifold 40 which is rotated by suitable means, such as a motor 4|. The entire assembly of spray and motor is mounted upon a cover 42 which is secured to a flange 43 of the casing III which surrounds an inspection opening 44 and is of a size such that the entire spray means may be removed therethrough as a unit. The motor 4| is shown as mounted on-a bracket which is secured to the'cover 42 and drives a shaft 4'! which extends through a supporting tube 48 and drives, by means of a pair of bevel gears 49, a shaft 60 on which the spray is mounted. The tube 48 may be secured to the cover 42 by suitable means and a packing gland ll of-standard construction may be provided for making a gas-tight seal with the shaft 41.

The shaft 50 of the spray 40 may comprise a hollow pipe extending through a bearing 52, such as a labyrinth-bearing, to a chamber 53. A supply pipe 54, extending through the communicates with this chamber for supplying the spray liquid through the rotating shaft 50 to the spray 40. It is to be understood,

that other driving means may be provided. The spray forexample, maybe driven by the action of therising gases or by the reaction of the spray itself or the plate 22 by a small number of nozzles due to the fact that the spray is usually cone-shaped and does not By the use of a rotating spray, however, the uniform washing of all portions of the under surface of the plate22 is assured while using a minimum quantity of washing or scrubbing liquid. The liquid from the spray nozzles "is carried upwardly'through the orifices 22 by the much thereof is set forth uniformly cover the entire wetted area.v

1 1 e es and forms a blanket of liquid above the plate 22. The thickness of this blanket of liquid'is determined by an overflow pipe which extends through the plate 22 into a well 6|, which forms a liquid seal from which the liquid overflows to the bottom I] of the apparatus. An inspection port 51, closed by a cover 58, may bev provided above the plate 22.

In an apparatus of this type which utilizes the velocity of the gas to effect cleaning, it is desirable to control the velocity through the orifices 23. For various reasons, such as a change in load, the total volume of gas or air to be cleaned may vary. However, any change in volume of gas'passed through the orifices 22 alters the velocity thereof. To overcome this and to provide adjusting means so that the velocity at various loads may be maintained constant or so that suitable control of the velocity of any given load may be made, I have provided a plate 82 which is disposed beneath the plate 22 and is adapted to close off and cover a selected number of orifices 23a. This plate 62 is slidably held in channels 63 which may be formed on or secured to the under side of the plate 22. In the embodiment shown the plate 82 is adapted to slide beneath a flange 64 (Fig. 3) by which the plate 22 is supported. The channels 63 may, of course, be attached to this flange 64. The plate 22 is provided with a lip 65 of a thickness corresponding to that of the flange 64 so as to effectively close off the selected orifices 23a. The plate 62 may be operated by suitable means such as a link 66 attached to an ear 61 secured to the plate 62. The link I! may extend outwardly through a bushing 68 formed in the casing l0 and may be provided with a suitable operating handle 69. It is to be understood, of course, that the plate 62 may be of any desired size depending upon the range of adjustment required or a plurality of suchplates may be employed. Other means for blocking oif, rendering ineffective, or varying the size of the apertures may be used ifdesired, such for example as closing 03 a part of the area of the casing above the cleaning zone.

The gas, after passing upwardly through the secondary cleaning zone 2| above described, has been completely freed from the entrained solid particles. It may however, have picked up droplets of the scrubbing liquid which may be carried alongtherewith to the upper portion of the casing III. In order to remove this entrained liquid a'set of curved vanes I0 is provided above the secondary cleaning zone 2| and below the conical top l4. These curved vanes 10 extend radially between a central cup II which forms a central closure therefor and an outer ring 12, which is held by a fiange 12 to the casing Ill. The flange I2 and ring 12 form an annular chanml 16 in which liquid is collected as it flows down the inner wall of the casing. The vanes are accurately located in spaced relationship to one another and are curved with their lower portions substantially vertical and with their upper portions substantially horizontal and in overlapped relationship to provide a decreasing area for gas flow as the gas passes upwardly therethrough. They are preferably formed with their outer edges curved to a larger radius than their inner edges'so' as to impart a rotational movement to the gas and to cause the greater portion of the gas to fiow out near the periphbefore striking liquid which is thus thrown out against the wall of the casing is collected in the channel 16 and is drained through a pipe 11 entering a cup 18 which efiects a liquid seal, from which it overflows onto the plate 22. The conical top Operation In the operation of this device the gas or air,

20 heavily laden with dust, fume or other matter,

enters through the tangential inlet opening it and is caused to whirl or rotate within the casing l0, whereby a large portion of the dust, fume or the like is removed centrifugally from the gas stream and falls to the bottom of the casing.

The gas then travels spirally upward and is subjected to the action of the slowly rotating sprays which feed the liquid upwardly with the gas flow onto the plate 22 and the baille-grid 24.

80 The rotating; sprays completely wash the bottom of the plate 22 and create'a fine mist which passes throughthe orifices 23 along with the gas stream and suspended particles. The gas, suspended particles and mist strike the baiiles 26 above the orifices. 23 and the suspended particles are trapped by the mist and water which collects on the top of the plate 22 to a predetermined depth depending upon the height of the overflow pipe 64. 4 Liquid is maintained on the plate 22 due to the velocity of the gas passing through the orifices. Excess liquid collecting on the plate flows. downwardly through the liquid seal formed by the cup GI. by causing the particles toimpinge upon the baille-grid 24 and to be entrappedin the liquid on the plate 22, then passes upwardly through the vanes 10 by which a violent rotational motion is imparted thereto. The. entrained liquid particles are caused to coalesce on the under side of the vanes due to the wiping action of the gases and are thrown off against the shell and top as large drops or sheets, thus drying the gas and relieving it of all entrained material. The 68 liquid collecting in the channel 16 flows downwardly through the tube ll onto the plate 22 above mentioned. As the gas leaves the vane I0, it tends to flow rapidly upward in spiral motion and to carry the coalesced liquid along so therewith. Hence the conical top I assists in collecting and removing the entrained mist and cooperates with the vanes 10 in eflecting the desired efiicient drying operation.

It will be noted that in the construction above 68 described, a small number of nozzles are slowly rotated. In this way a complete coverage of the bottom surface of the plate 22 is obtained by the use of a minimum number of nozzles and the minimum quantity of liquid is required. The 70 velocity of the gas through the plate 22 is adjusted by means of the plate 62 in conjunction with the quantity of the scrubbing liquid so as to maintain the desired depth of liquid on the plate and to remove the liquid, together with the II entrained particles, through the overflow pipe at Gas which has'thusbeen cleaned" a rate dependentupon the rapidity with which liquid is introduced into the gases by the spray. By suitably regulating the various features above mentioned, the ilow of liquid is maintained at a minimum, hence the scrubber may be so operated that the cooling effect on the hot gases is practically negligible. The invention accordingly provides a simple and efficient scrubber which occupies the minimum amount of space, requires only a comparatively small amount of 10 power to operate and is well adapted for large scale industrial use.

Although a specific embodiment of the invention has been set forth'for purposes of illustration, it is to be understood that various changes 15 and modifications may be made therein and that the invention is capable of various uses, as will be readily apparent to a person skilled in the art. Certain specific terms have been used herein for convenience of description and not as a limita- 30 tion of the scope of the invention. The invention is only to be limited in accordance with the following claims.

What I claim is:

1. An apparatus for cleaning gases comprising an upright casing, a cleaning zone in said casing comprising a transverse plate having a plurality of openings therein forming orifices through which the gas passes at high velocity, bailie means disposed above and in registration with said orifices in a position such that the gas and the entrained matter impinge thereon, a cleaning spray comprising nozzles located belozr said plate and positioned to direct cleaning liqu ri toward the lowersuriace thereof and through 35 said orifices for continuously washing said lower surface and preventing said orifices from becoming clogged due to deposition of entrained particles from. said gases, means passing the gases to be cleaned upwardly in said casing under sufilcient pressure to carry said cleaning liquid upwardly through said orifices and to form a blanlret of cleaning liquid on. said plate, and overfiow means associated with said plate for maintaining said-liquid at apredeterminedlevel 45 thereon, said. overflow means discharging to the lower part of said casing.

2. An apparatus for cleaning gases comprising an upright cylindrical casing, means passing gases to be cleaned upwardly therein, a cleaning zone comprising a transverse plate having a plurality of openings therein forming orifices through which the gas passes at high velocity, liquid spray means comprising nozzles positioned below said plate to direct a cleaning liquid toward the under surface thereof, and through said orifices, said casing having an inspection opening below said plate of suflicient size to permit the spray means to pass therethrough, a I cover for said inspection opening, and a liquid supply pipe for said spray means extending through said cover, said spray means being secured to said cover and supported thereby for removal from said casing as a unit.

3. An apparatus for cleaning gases comprising 65 an upright cylindrical casing, means passing gases to be cleaned upwardly therein, a cleaning zone comprising a transverse plate having a plurality of openings therein forming orifices through which the gas passes at high velocity, said casing having an inspection opening below said plate, a cover for said opening, sp means comprising a set of nozzles mounted on Sa Cover and positioned within said casing to direct a spray oi cleaning liquid toward the under surorifices in a position such 7 entrained matter impinge f thereon, a cleaning face of said plate and'through said orifices, and

driving means, said drivingmeans being for ro tating said spray means mounted on said cover whereby the spray means'and driving means may be removed from said casing as a unit.

v4. 'An apparatus for cleaning gases comprising an upright cylindrical casing, means passing gases to be cleaned upwardlytherein, acleaning zone comprising a transverseplatehavinga plurality of openings "therein 'jforjming orifices through which the gas passes at high ,Veldcity, said casing having an inspection opening below said plate, acover'for said opening, spray means comprising a set of'nozzles mounted on said cover and positioned within said" casing to direct a spray of cleaning liquidtoward the under surface of said plate-through said orifices, drivin'g means for rotating said spray means, comprising-a. motor mounted on theoutside of said cover and a drive shaft extending through said cover to interconnect said"n1otor and said spray means, and liquid supply means for said spray also extending through said cover whereby the spray and associated mechanism may be re moved as a unit from said casing.

5. An apparatus for cleaning gases comprising an upright casing, a cleaning'zone in said casing comprising a transverse plate having" a' plurality of openings therein forming orifices through which the gas passesat high velocity, bafiie means disposed above'and in ream-man" with said spray/comprising *n 'oiz'zles said plate and positioned to direct cleaning liquid toward the lower surface thereof and through said orifices in the direction of gas'flow for continuously washing said lower surface and preventing said orifices from becoming clogged due to deposition 5 of entrained particles from said gases and means passing the gases to be cleaned upwardly in said casing under sufliicient pressure to carry said cleaning liquid upwardly through said orifices and to form a blanket of cleaning liquid on said 10 plate.

6. An apparatus for cleaning gases comprising an upright casing, a clcaningzone in said casing comprising a stationary-transverse plate having a plurality of openings therein forming orifices 1.

through which the gas passes at high velocity, baflle means disposed above and in registration with said orifices in a position such that the gas and the entrained matter impingethereen. a

cleaning spray comprising nozzles located below 2 ROBERT R. HARMON.

{'CER'ITIFICATE 0F CORRECTION.

rat rs-u ,23231???" f Decezsber 21 191w.

ROBERT B. HARHON. y jcertifiecfij error appears in the printed specification I ofitb'lbiifvte lfiornoered patent requiring correction as follows: Page )4, first -column;, line 2, ola'ixi ifi fstrike out the comma and words said driving means insert :theis ame before "mounted" in line 5, same claim;

lagiq that the saiid netters' Patent should be read with this correcti on therein that theQSaSfie niayiconforxfirltothe record of the case in the Patent Office.

Signed sealed this 18th day of February, A. D. 1914.1.

Henry Van Arsdale, 8ea1) Acting Commissioner of. Patents. 

